1. Field of the Invention
The present invention relates to a method of production controlling a wire harness for use in vehicles or industrial or household appliances.
2. Prior Art
A wire harness, for example, for a vehicle comprises many sections, including an engine compartment harness, a main harness, a cabin harness, a front door harness and so on. (see, e.g., FIG. 9) The circuitry of each of these harness sections differs depending on the car model, engine model, door model (hereinafter referred to as a car model), the grade of specification. A harness number is assigned to each of the different circuits of different harness sections. That is, production control and manufacture of the wire harness are conducted for each of these harness numbers. For example, assuming that the main harness of a certain car model contains, in addition to the basic or normally installed equipment such as a ratio, air conditioner, and a trunk compartment lamp, some of four selectable electrical systems, including a four wheel drive system, an electronic control suspension system, an anti-lock braking system and a keyless entry system (a system in which the car door can be opened/closed by means of a card), 16 different harness numbers are required to cover all possible combinations of these four electrical systems. This applies not only to the main harness but also to each of the other harness sections, including an engine compartment harness, cabin harness, and front door harness. Further, there are 16 different harness numbers for every harness section of every car model. The wire harness for a single vehicle is constituted of a combination of harnesses bearing particular harness numbers of respective harness sections which are determined by a combination of selected electrical systems.
However, there is a tendency towards an increase in the number of harness numbers due to diversification of car models, grades or specifications, and thus there is a tendency towards small-scale variated production of wire harnesses, making production control difficult. That is, an increase in the number of harness numbers makes production control of a wire harness troublesome and mass production impossible, thereby resulting in a decrease in productivity. Furthermore, since a wire harness is manufactured corresponding to each of harness numbers, when a variation in the production quantity of a harness occurs, manufacture of the entire harness section must be corrected to re-adjust the production quantity, thus making the manufacture difficult. Particularly, in the case of wire harnesses for vehicles, a change in the combination of electrical systems brings about a change not only in a single harness section but also in the harness numbers of all the other harness sections, making the manufacture difficult. Furthermore, when a change in design occurs, the manufacture of the entire harness circuit must be corrected to adjust the circuit configuration, making manufacture difficult.
Conventionally, a production system of an automobile manufacturer employs matrix data, comprising a combination of digits, letters and symbols for the automobile manufacturer to receive an order from a dealer. The matrix data indicates a combination of harness numbers which constitute an entire harness system in a single vehicle which differs depending on the car model, grade, specification or the like. The dealer inputs from a terminal machine thereof the matrix data of the vehicle that the dealer has received from a customer, whereby the orders from respective dealers are accumulated in a computer in a production control department of the automobile manufacturer. The automobile manufacturer adds up the data periodically, and puts in an order of wire harness to a harness maker. Thus, the production control department of an automobile manufacturer analyzes harnesses required for every harness section and every car model, i.e., for every harness number, adds up the required number, and puts in an order to the harness maker. The harness maker is required to control the production quantity such that a combination of harness numbers of respective harness sections matches the ordered vehicle number, making the control troublesome. Furthermore, when a cancellation of or a change in the order from the dealer occurs after the order has been made, addition must be performed again, making the production control a time-consuming task.